Electric lamps which operate at high temperatures, typically lamps having a halogen containing fill, usually use current supply connections by melting a foil into a press or melt seal. Such lamps, typically, are halogen incandescent lamps or metal halide discharge lamps. The lead-in connection, of course, must be vacuum-tight.
The temperature range in the region of the pinch or press seal, where the foils are melted-in within the glass, may reach 350.degree. C. and more. Such temperatures arise particularly in highly thermally loaded lamps. The high temperature may cause penetration of atmospheric oxygen by capillary spaces surrounding the external current supply leads. The atmospheric oxygen which thus may penetrate results in corrosion of the foils at the high temperature to which they are exposed. It has been proposed to seal such capillary spaces by a low melting point glass, which may be referred to as a solder glass or a filler glass or a sealing glass, for short hereinafter "sealing glass". Usually, the glass is a lead borate glass, which frequently has ZnO and SiO.sub.2 added thereto (see, for example, the referenced U.S. Pat. No. 2,889,952). Such known lead borate glasses, however, may lead to increased corrosion of the current supply elements made of molybdenum wire, and further have unsatisfactory flow characteristics in the region of between 350.degree. C. to 500.degree. C.
It has been proposed to provide sealing glasses based an antimonyborate glasses--see for example U.S. Pat. No. 3,588,315. These glasses do not have corrosive effects on the molybdenum wire. Yet, the use of such sealing glasses is undesirable due to health reasons; they pose a substantial health risk.